WATER - Water among Cubes

给定一个$n*m$的场地，每一个格子上有高度为$h_{ij}$的长方体，现在突然下雨了，问能存多少水？ 多组数据，输入输出格式见样例 Translated by @partychicken

On a rectangular mesh comprising _n\*m_ fields, _n\*m_ cuboids were put, one cuboid on each field. A base of each cuboid covers one field and its surface equals to one square inch. Cuboids on adjacent fields adhere one to another so close that there are no gaps between them. A heavy rain pelted on a construction so that in some areas puddles of water appeared. ### Task Write a program which: - reads from the standard input a size of the chessboard and heights of cuboids put on the fields, - computes maximal water volume, which may gather in puddles after the rain, - writes results in the standard output.

The number of test cases t is in the first line of input, then t test cases follow separated by an empty line. In the first line of each test case two positive integers 1 <= _n_ <= 100, 1 <= _m_ <= 100 are written. They are the size of the mesh. In each of the following _n_ lines there are _m_ integers from the interval \[1..10000\]; _i_-th number in _j_-th line denotes a height of a cuboid given in inches put on the field in the _i_-th column and _j_-th raw of the chessboard.

Your program should write for each tes case one integer equal to the maximal volume of water (given in cubic inches), which may gather in puddles on the construction.

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3 6
3 3 4 4 4 2
3 1 3 2 1 4
7 3 1 6 4 1

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